It absolutely targets a problem that exists. Even in places with pretty great public transit, there is some demand for taxis/Uber/etc. Oftentimes even moreso, because if I don't need a car for 90% of trips, I might not have a car at all. So I use an Uber or a taxi when a certain trip demands it.
By far the worst part about said Ubers and Taxis is the driver. They're an unpredictable element in a situation where I greatly appreciate predictability. Unlike my parents, I didn't grow up with staff, so I'm not used to simply pretending this person I'm sharing a space with doesn't exist. Instead, I need to navigate the fuzzy line between courtesy and service.
Waymos have none of this shit. They're clean, show up when they say they will, I can play my own music, adjust the air conditioning, and have obnoxious conversations with my friends. They drive safely, and, as a cherry on top, they're cool as hell.